X Ray is an electromagnetic wave of high energy and very short wavelength, which is able to pass through many materials opaque to light.

X-rays make up X-radiation, a form of electromagnetic radiation

Before x ray machines were invented, broken bones, tumors and the location of bullets were all diagnosed by physical examination and a doctor’s best guess. Patients paid the price of these approaches.

Then on November 8th of 1895, a German physics professor Wilhelm Conrad Roentgen made a remarkable discovery. He took a tube similar to fluorescent light bulbs, removed all the air and filled it with a special gas.

When he passed a high electric voltage through it, the tube gave off a fluorescent glow. Roentgen then covered the tube with heavy black paper and once again passed electricity through it and noticed a barium coated screen across the lab began to glow.

He quickly realized his tube was emitting an “invisible light” or ray, and this ray could pass through the heavy paper covering the tube. He quickly did more experiments and discovered these new rays could pass through most substances and would cast shadows of solid objects on pieces of film.

He named the new ray X-ray, because in mathematics “X” is used to indicated the unknown quantity.